The invention relates to tampons in general, especially to digital and applicator type catamenial tampons. More particularly, the invention relates to improvements in tampons of the type wherein a wad or pledget of absorbent material is confined in an envelope of foraminous sheet material (called coverstock).
It is well known to confine a pledget of absorbent material (such as cotton or rayon) in an envelope of foraminous sheet material (hereinafter called coverstock for short) so that the fibers of the pledget are prevented from remaining, or are less likely to remain, in the vagina or in another body cavity which receives the finished tampon, either as a result of digital insertion or with the assistance from an applicator. As a rule, coverstock is supplied by the makers of such products in the form of large rolls which are subdivided into blanks for draping around discrete pledgets of absorbent material. In many instances, pledgets are in the form of cylinders called memory cylinders due to their tendency to expand subsequent to (a) draping into coverstock and (b) compression in directions to reduce their diameters to a fraction of the diameter of an uncompressed and undraped cylinder.
In accordance with a presently known proposal, memory cylinders are draped into square blanks of coverstock. One end face of a cylinder to be draped is placed against the central portion of the square blank, and the remaining portion of the blank is folded or draped against the peripheral surface of the cylinder. This results in conversion of the originally square blank into a cup with a bottom end wall which overlies the one end face of the cylinder and with a cylindrical wall which surrounds a substantial portion of the peripheral surface of the cylinder. The cup has a rim with alternating hills and valleys. The hills have tips which project beyond the other end face of the cylinder, and the deepmost portions of the valleys are located between the two end faces. The tips of the hills can be folded over the other end face of the cylinder in order to ensure that at least a portion of the other end face is also overlapped by the material of the coverstock.
In accordance with another prior proposal, coverstock is converted into a bag which confines the pledget of absorbent material not unlike a tea bag confines a supply of tea leaves. It was also proposed to weld the folds or pleats which develop along the peripheral surface of a memory cylinder in order to enhance the stability of the envelope of coverstock. A drawback of such proposal is that the welded pleats resist expansion of confined absorbent material when the latter is in the process of gathering menses or other body fluids.